For the linear LSQ solvers that can be used to compute local subdomain control point solution \(\vec{P}\) , there are a variety of choices available. Direct methods like Singular Value decomposition or Cholesky decomposition operating on the normal equations [1]} can compute optimal values. Alternatively, the iterative LSQ solvers such as orthogonal decomposition methods based on QR and QZ factorizations are more stable, especially when the normal form of the operator, \(R^T R\) , is ill-conditioned.
